The present invention generally relates to a push-button switch employed for controlling the supply of electricity in various kinds of electronic appliances such as an audio instrument, etc.
Generally, as a push-button switch of the type referred to above, such one as is equipped with an illumination unit which accommodates a light emitting element like a light emitting diode, etc. therein has been well-known. More specifically, the prior art push-button switch is so constructed that a light emitting diode LED is held by a lamp holder which is accommodated within a lamp casing, and at the same time the lamp casing is covered by a covering through a light diffusion disk, thereby forming an operation unit actuated in association with the depressing operation of the switch. In this prior art switch, since the operation unit is arranged to be engaged with a plunger, the switching mechanism is controlled to be turned on or off by the depressing operation of the operation unit, through the plunger, simultaneously with which the LED is illuminated.
However, since the aforementioned LED has polarity, and therefore is likely to be improperly inserted into the lamp holder. That is, the LED is likely to be inserted into the holder backwards so that the polarity of the LED is reversed and no light is emitted.
The illumination unit as described above is generally composed of a light emitting element, a holder which holds the light emitting element inside thereof, a lamp casing for accommodating the holder therein, and a light diffusion disk provided on the lamp casing through a covering.
These components are integrally formed into the illumination unit so as to be installed in a housing which is a main body of the push-button switch. However, when the illumination unit is depressed within the range of a given stroke, both the LED and the holder should be moved upwards and downwards relatively to each other within the lamp casing while they are secured to the housing. Moreover, each of these component parts such as the LED and holder is considerably small in size, and therefore, it is inconvenient that some tool, for example, pair of pincers is required in assembling the component parts.